The locale is the Caldecott Tunnel Fourth Bore between Orinda and Oakland. Imagine the time is the late Miocene period, about 10 million years ago. The climate is warmer and abundant greenery flourishes. Gone are the rugged, rocky hills, the freeways, the cities. In their place is a verdant river flood plain where small, rodent like creatures nest in the savannah grassland, and antelope and gazelle graze peacefully on lush foliage. Let your imagination move forward several million years to the Pleistocene period, a mere one million years ago. The scene is much the same, but suddenly the earth trembles. An enormous hairy creature emerges from the thick undergrowth and lumbers toward the river to drink. It’s a giant sloth bigger than a 17-person van.
This is the picture geologist Jim Allen creates of what the tunnel locale used to look like, partially from fossils similar to those being found in the Caldecott Fourth Bore excavation. Jim will share the discoveries paleontologists have found at the Lafayette Library and Learning Center, part of the Lafayette Historical Society’s (LHS) speakers series.
Along with Jim, Caldecott Fourth Bore public information officer Ivy Morrison will give an overview of the tunnel progress and a glimpse of the complicated excavation process. The Fourth Bore project is a partnership between the California Department of Transportation (Caltrans), the Contra Costa Transportation Authority (CCTA) and the Alameda County Congestion Management Agency (ACCMA).
Jim will bring rock samples from both the eastern (Orinda) and the western (Oakland) excavations, showing how different the rock formations are on each side of the tunnel. The tunnel is projected to open to traffic in 2013 and to be completely finished with all landscaping in 2014. A complete history of the tunnel, the excavation process and photos are available on the website www.caldecott-tunnel.org.
For more information or to make reservations for the June 14 presentation call 925-283-1848 or send an email to lafayette.history@comcast.net. Or visit the History Room in the Library and Learning Center – enter on Golden Gate Way
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